(1) Summary of the Invention
The present invention relates to a method for inhibiting psychrotrophic bacteria in finished cream or milk based products using a Pediococcus, preferably Pediococcus pentosaceus. In particular, the present invention relates to a method wherein the Pediococcus generates antimicrobic metabolites, particularly hydrogen peroxide, in Cottage cheese and other cream or milk based products at refrigeration temperatures used for storage.
(2) Prior Art
The use of Streptococcus lactis subspecies diacetylactis in Cottage cheese to inhibit psychrotrophic bacteria is described in U.S. Pat. No. 3,968,256 to Sing; U.S. Pat. Nos. 3,975,545 and 4,191,782 to Vedamuthu, and U.S. Pat. No. 4,477,471 to Gonzalez. This bacterial species produces an inhibitory substance in the Cottage cheese and other finished cream or milk based products which inhibits psychrotrophic bacteria. This species works well; however, there is a need for longer term inhibition of the psychrotrophic bacteria than is produced by the inhibitory substance produced by Streptococcus lactis subspecies diacetylactis.
Pediococci are used in meat and vegetable fermentations, and the like. Pediococci have not been used to any significant extent in the fermentation of milk based products since they are not as effective in this application because they do not grow well in milk. It is known that some Pediococci generate inhibitory substances called "bacteriocins" which inhibit other bacteria as discussed in Graham et al Appl. and Envir. Microbiol. 50, 532-534 (1985) which might be useful in fermented foods; however, where the food is not fermented by the Pediococci the bacteriocin would not be expected to be produced in significant amounts. There has been no suggestion by the prior art of the use of Pediococci in finished Cottage cheese or other cream or milk based products without fermentation for any purpose.